Strapdown inertial navigation system. Part-2 – Error models

Almost all new aircraft are equipped with the Inertial Navigation System (INS). The accuracy in calculations of velocity, position and attitude of aircraft depends on measurement Instruments, initial alignment errors, and navigation computer errors and can be improved by analysing and solving of differential equation of error. Solution of the equations allows one to correct output signals from the navigation system. In this work, three error models for the Strapdown Inertial Navigation System (SDINS) are derived – one into computed co-ordinate system in matrix notation and two models in a local-level co-ordinate system, in matrix and in quaternion notations, respectively. Some simplifications to be introduced into error equations are proposed.